Virtual reality, immersive simulation, artificial reality, telepresence, virtual world, virtual environment and similar terms are used to describe a viewer-display interface in which successive images are presented and controlled as to content by gestures, by walking around, looking around and using the viewer's hands to simulate the manipulation of objects. But since the images are effectively presented at infinity there is a problem in presenting such images of near objects without discomfort in the viewer's eyes. When close objects are presented, the feeling of discomfort arises because an image at infinity is viewed with accommodation for infinity with a high degree of convergence of the viewer's eyes. This sense of discomfort makes such a presentation of successive images hard to accept and is not easy to look at, especially for long periods. It would be advantageous to be able to provide both close and distant successive images for virtual reality without discomfort.
In the past, a static kind of virtual reality was provided by the parlor stereoscope. It was used to present stereograms taken from differing perspectives corresponding to the separation between human eyes, more or less, to provide a striking illusion of depth. Since such stereograms typically show a distant scene there is little discomfort to the human visual apparatus. However, if "near" objects are presented, as above, the same discomfort arises.
On the other hand, stereo image pairs are now increasingly used for various purposes, including everything from motion pictures to clinical diagnosis. In recent years, the presentation of successive stereopair images has been by means of television. These images have also typically presented both near and far objects as if from infinity. It would be advantageous to be able to provide virtual reality and similar successive image techniques in stereo embodiments that would enable viewing of close "objects" but would eliminate discomfort arising from viewing such close "objects" imaged as if from infinity.
As known, computer imaging calls for extraordinarily high amounts of memory. Virtual reality also suffers from very high speed demands. In fact, there is unfortunately a perceptible lag in the image response of present day hardware. In other words, the viewer will execute movements that will call for changes in the content of the images presented but the hardware will only be able to provide such changed images to the viewer after a delay that makes the viewer wait for the images to "catch up." See Looking Glass Worlds, by Ivars Peterson, Science News, Jan. 4, 1992, Vol. 141, No. 1, pp. 8-10, 15. It would be advantageous to speed up the process and reduce or eliminate the lag.